Low selectivity deposition methods

ABSTRACT

A deposition method includes forming a nucleation layer over a substrate, forming a layer of a first substance at least one monolayer thick chemisorbed on the nucleation layer, and forming a layer of a second substance at least one monolayer thick chemisorbed on the first substance. The chemisorption product of the first and second substance may include silicon and nitrogen. The nucleation layer may comprise silicon nitride. Further, a deposition method may include forming a first part of a nucleation layer on a first surface of a substrate and forming a second part of a nucleation layer on a second surface of the substrate. A deposition layer may be formed on the first and second parts of the nucleation layer substantially non-selectively on the first part of the nucleation layer compared to the second part. The first surface may be a surface of a borophosphosilicate glass layer. The second surface may be a surface of a rugged polysilicon layer. The first and second part of the nucleation layer may be formed simultaneously.

TECHNICAL FIELD

This invention relates to methods of atomic layer deposition and methodsof low selectivity chemical vapor deposition.

BACKGROUND OF THE INVENTION

Atomic layer deposition (ALD) is recognized as a deposition techniquethat forms high quality materials with minimal defects and tightstatistical process control. Even so, it is equally recognized that ALDcan have limited application. In some circumstances, the theoreticallyexpected quality of an ALD layer is not achieved.

It can be seen that a need exists for an ALD method that forms a layerwithout, introducing intolerable defects into the material.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the invention are described below withreference to the following accompanying drawings.

FIG. 1 shows a cross-sectional fragmentary view of a depositionsubstrate at one processing step in accordance with an aspect of theinvention.

FIG. 2 shows the deposition substrate of FIG. 1 at a processing stepsubsequent to that shown in FIG. 1.

FIG. 3 shows the deposition substrate of FIG. 1 at an alternativeprocessing step subsequent to that shown in FIG. 1.

FIG. 4 shows the deposition substrate of FIG. 1 at a processing stepsubsequent to that shown in FIG. 3.

FIG. 5 shows a cross-sectional fragmentary view of a semiconductivewafer portion at a processing step in accordance with an aspect of theinvention.

FIG. 6 shows the semiconductive wafer of FIG. 5 at a processing stepsubsequent to that shown in FIG. 5.

SUMMARY OF THE INVENTION

One aspect of the invention provides a deposition method that includesforming a nucleation layer over a substrate, forming a layer of a firstsubstance at least one monolayer thick chemisorbed on the nucleationlayer, and forming a layer of a second substance at least one monolayerthick chemisorbed. on the first substance. A chemisorption product ofthe first and second substance may include silicon and nitrogen, oraluminum and oxygen, or tantalum and oxygen. Also, the nucleation layermay comprise silicon nitride, aluminum oxide, or tantalum oxide. Athickness of the. nucleation layer may be less than about 20 Angstroms.

In another aspect of the invention, a low selectivity deposition methodincludes forming a first part of a nucleation layer on a first surfaceof a substrate and forming a second part of a nucleation layer. on asecond surface of a substrate. A deposition layer may then be formed onthe first and second parts of the nucleation layer substantiallynon-selectively on the first part of the nucleation layer compared tothe second part. Substantially non-selective deposition occurs eventhough the first and second surfaces of the substrate exhibit a propertyof the deposition layer forming less readily on the first surfacecompared to the second surface. The deposition layer may comprise amonolayer of a first chemisorbed specie. The deposition layer may beformed by chemical vapor deposition or atomic layer deposition. Thefirst and second part of the nucleation layer may be formedsimultaneously. Also, the nucleation layer may form substantiallynon-selectively on the first surface of the substrate compared to thesecond surface. Further, a thickness of the first part of the nucleationlayer may be. greater than 50% of a thickness of the second part, oreven greater than 80% of the thickness of the second part. The firstsurface of the substrate may exhibit a property of chemisorbing thefirst specie at a slower rate compared, to the second surface.

In another aspect, a deposition method includes simultaneously forming afirst part of a nucleation layer on an insulative oxide material and asecond part of the nucleation layer on a semiconductive material. Thenucleation layer may be contacted with an initiation precursor. Aninitiation layer at last one monolayer thick may be formed on the firstand second parts of the nucleation layer substantially non-selectivelyon the first part of the nucleation layer compared to the second part.

In another deposition method, a nucleation layer comprising silicon andnitrogen may be formed substantially non-selectively on a first and asecond surface of a substrate. A monolayer of a first substance may bechemisorbed on the nucleation layer. A monolayer of a second substancemay be chemisorbed on the first substance, wherein a chemisorptionproduct of the first and second substances comprises silicon nitride.

In a still further aspect, a deposition method may include atomic layerdepositing a nucleation substance chemisorbed on a first surface and asecond surface of a substrate substantially non-selectively. The firstsurface may exhibit a property of chemisorbing an atomic layerdeposition precursor at a slower rate compared to the second surface.Also, the nucleation substance may exhibit a property of chemisorbingthe precursor at an approximately equal rate over the first surfacecompared to over the second surface.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This disclosure of the invention is submitted in furtherance of theconstitutional purposes of the U.S. Patent Laws “to promote the progressof science and useful arts” (Article 1, Section 8).

Atomic layer deposition (ALD) involves formation of successive atomiclayers on a substrate. Such layers may comprise an epitaxial,polycrystalline, amorphous, etc. material. ALD may also be referred toas atomic layer epitaxy, atomic layer processing, etc. Further, theinvention may encompass other deposition methods not traditionallyreferred to as ALD, for example, chemical vapor deposition (CVD), butnevertheless including the method steps described herein. The depositionmethods herein may be described in the context of formation on asemiconductor wafer. However, the invention encompasses deposition on avariety of substrates besides semiconductor substrates.

In the context of this document, the term “semiconductor substrate” or“semiconductive substrate” is defined to mean any constructioncomprising semiconductive material, including, but not limited to, bulksemiconductive materials such as a semiconductive wafer (either alone orin assemblies comprising other materials thereon), and semiconductivematerial layers (either alone or in assemblies comprising othermaterials). The term “substrate” refers to any supporting structure,including, but not limited to, the semiconductive substrates describedabove.

Described in summary, ALD includes exposing an initial substrate to afirst chemical specie to accomplish chemisorption of the specie onto thesubstrate. Theoretically, the chemisorption forms a monolayer that isuniformly one atom or molecule thick on the entire exposed initialsubstrate. Practically, as further described below, chemisorption mightnot occur on all portions of the substrate. Nevertheless, such animperfect monolayer is still a monolayer in the context of thisdocument. The first specie is purged from over the substrate and asecond chemical specie is provided to chemisorb onto the first monolayerof the first specie. The second specie is then purged and the steps arerepeated with exposure of the second specie monolayer to the firstspecie. In some cases, the two monolayers may be of the same specie.Also, additional species may be successively chemisorbed and purged justas described for the first and second species.

ALD is often described as a self-limiting process, in that a finitenumber of sites exist on a substrate to which the first specie may formchemical bonds. The second specie might only bond to the first specie adthus may also be self-limiting. Once all of the finite number of siteson a substrate are bonded with a first specie, the first specie willoften not bond to other of the first specie already bonded with thesubstrate. However, process conditions can be varied in ALD as discussedbelow to promote such bonding and render ALD not self-limiting.Accordingly, ALD may also encompass a specie forming other than onemonolayer at a time by stacking of a specie, forming a layer more thanone atom or molecule thick. The various aspects of the present inventiondescribed herein are applicable to any circumstance where ALD may bedesired. A few examples of materials that may be deposited by ALDinclude silicon nitride, zirconium oxide, tantalum oxide, aluminumoxide, and others. Examples of specie pairs for ALD of silicon nitrideinclude NH₃/SiHCl₃ and others.

ALD offers a variety of advantages and improvements over other methodsof forming materials on a substrate. However, ALD layers formed on asubstrate may also possess thickness variations caused by variations inthe composition and/or surface properties of the underlying substrate.Such disadvantage can limit the application of ALD methods to excludeapplications where ALD might otherwise be particularly advantageous.

For example, when a material is to be deposited simultaneously overmultiple types of substrates or over a single type of substrate havingdifferent surface properties, ALD may be a poor candidate for formingthe material. Experience indicates that material formed by ALD may notform at a uniform rate on differing types of substrates or on a singletype of substrate having multiple surface properties in multiple areas.The different rates of formation produce defects and/or varyingthicknesses in the deposited material. Accordingly, even though ALD maybe used to form very thin layers of material, thickness variations mayproduce unacceptable defects.

For example, a layer of polysilicon may include isolated areas where asurface defect reduces the likelihood of formation of a material on thesurface defect by ALD. The differences in deposition rate may createthickness variations in the deposited material. Also, for example, adesire may exist to simultaneously deposit a material over twodissimilar types of substrate. A surface of borophosphosilicate glass(BPSG) and a surface of polysilicon can be two dissimilar types ofsubstrate. Observations indicate that formation of silicon nitride byALD simultaneously on BPSG and polysilicon produces a thicknessvariation in the deposited silicon nitride. The thickness of the siliconnitride deposited on the BPSG can be less than 50% of the thickness ofthe silicon nitride deposited on the polysilicon. A variety of othercircumstances are conceivable wherein a substantially uniform thicknessof a material deposited by ALD is desired on dissimilar portions of asubstrate, such as a semiconductive substrate compared to an insulativeor a conductive substrate.

According to one aspect of the invention, a deposition method mayinclude forming a nucleation layer over a substrate. The nucleationlayer may exhibit a first value of an electrical property, for example,dielectric constant, conductivity, current leakage, permitivity,capacitance, etc. Turning to FIG. 1, a substrate 2 is shown including afirst part 4 and a second part 6. Second part 6 may comprise acomposition different from first part 4 or second part 6 may comprisethe same composition but exhibit a property that causes deposition tooccur more readily on second part 6 compared to first part 4. FIG. 2shows a deposition layer 8 formed on first part 4 and second part 6 ofsubstrate 2. Notably, the thickness of deposition layer 8 that is overfirst part 4 is less than 50% of a thickness of deposition layer 8 thatis over second part 6.

There can be at least one advantage of providing a nucleation layer overa substrate prior to performing some types of deposition, for exampleALD. The nucleation layer may operate to provide at least somewhatuniform surface properties for the deposition and decrease thicknessvariations such as shown in FIG. 2. Even so, a nucleation layer mayinterface between a substrate. and a subsequently deposited depositionlayer in a manner that only insignificantly influences the overallproperties of the combined nucleation and deposition layer. That is, adeposition layer deposited directly on a substrate without a nucleationlayer generally will possess some designated purpose or designatedproperty. A nucleation layer may be selected such that only aninsignificant impact is imposed upon the desired purpose or property.Accordingly, a nucleation layer may find advantageous use even incircumstances where a substrate possesses both a homogeneous compositionand homogeneous surface properties. Such a nucleation layer mayinterface between a substrate and a deposition layer to enhance the rateof formation of the deposition layer or to otherwise provide anadvantageous property or result. For example, a first monolayer of afirst chemisorbed specie may form more rapidly over BPSG if a nucleationlayer is first formed.

In addition to composition and surface properties, the thickness of anucleation layer may also influence its suitability. At times, ALD isselected with the desire to form high quality very thin layers ofmaterial. A nucleation layer may be selected that only insignificantlyimpacts the deposition layer. However, as the thickness of a nucleationlayer increases and approaches or exceeds the thickness of a depositionlayer, the potential advantages of selecting ALD for forming a layer ofthe material may be diminished. At the optimum, a nucleation layerhaving a thickness of only one atom or molecule may be formed tominimize any potential impact. However, a more thick nucleation layermay also ii provide little impact. Accordingly, a thickness of anucleation layer may comprise less than about 20 Angstroms. Further, thethickness may comprise less than about 6 Angstroms. Still further, thethickness may comprise about 2.5 Angstroms. A monolayer of siliconnitride may comprise about 2.5 Angstroms.

In FIG. 3, a nucleation layer 10 is shown formed over substrate 2. Inthe illustration provided, substrate 2 includes first part 4 on whichdeposition occurs less readily compared to second part 6. As indicated,such a property may be caused by first part 4 possessing a differentcomposition than second part 6 or exhibiting a different surfaceproperty than second part 6. Such is in contrast to another advantageoususe of nucleation layer 10 even when a substrate possesses homogeneouscomposition and exhibits homogeneous surface properties.

As shown in FIG. 4, a deposition layer 12 may be formed on nucleationlayer 10 without the thickness variation illustrated in FIG. 2.Deposition layer 12 may be formed by any deposition method presentlyknown to those skilled in the art or later developed, but preferably byALD as defined herein. Other deposition methods may also be suitable. Inthe present aspect of the invention, a suitable deposition method mayinclude forming a layer of a first substance at least one monolayerthick chemisorbed on the nucleation layer and forming a layer of asecond substance at least one monolayer thick chemisorbed on the firstsubstance. A chemisorption product of the layers may comprise depositionlayer 12. Deposition layer 12 may exhibit a second value of theelectrical property exhibited by nucleation layer 10 at a first value.Examples of electrical properties are listed above. Deposition layer 12and nucleation layer 10 combined may exhibit a third value of theelectrical property that is more near the second value than the firstvalue. The third value and second value may be approximately equal. Themethod may include at least once additionally forming successivemonolayers of the first substance and the second substance. In suchcase, all monolayers may be comprised by deposition layer 12.

Nucleation layer 10 may possess a variety of compositions and exhibit avariety of properties and still comprise a suitable interface betweendeposition layer 12 and a substrate, for example substrate 2. Forexample, nucleation layer 10 may comprise a compound the same as adeposition product of the first and second substances in the chemisorbedmonolayers described above. For example, a chemisorption product of thefirst and second substance may comprise silicon and nitrogen. Anucleation layer may also comprise silicon and nitrogen. Morespecifically, the chemisorption product that produces deposition layer12 may comprise silicon nitride and nucleation 10 may also comprisesilicon nitride.

A nucleation layer may comprise an approximately homogeneouscomposition. In an approximately homogeneous composition, onlyinsignificant differences in composition exist throughout the nucleationlayer. However, a nucleation layer may also possess a compositionwherein one part of the nucleation layer differs from a composition ofanother part of the nucleation layer as to a component, a proportion ofa component, or both. One example is a nucleation layer that comprisessilicon nitride but a part of the nucleation layer further comprisesoxygen, for example, comprising silicon oxynitride.

In another aspect of the invention, a deposition method includes forminga first part of a nucleation layer on a first surface of a substrate andforming a second part of a nucleation layer on a second surface of thesubstrate. Forming the first and second part of the nucleation layer mayoccur simultaneously. Alternatively, the first part and the second partof the nucleation layer may be formed separately. When formedsimultaneously, the nucleation layer may form substantiallynon-selectively on the first surface of the substrate compared to thesecond surface. The thickness of a nucleation layer is one measure ofthe selectivity of forming a nucleation layer. That is, non-selectiveformation of a nucleation layer may occur when the thickness of thefirst part of the nucleation layer on the first surface of a substrateis greater than 50% of the thickness of the second part formed on thesecond surface of the substrate. More particularly, non-selectiveformation occurs when the thickness of the first part is greater than80% of the thickness of the second part.

One advantage of the present invention is that substantiallynonselective formation of a nucleation layer may occur even though ALDon the same surface occurs selectively, that is, at a greater than 2 to1 ratio of deposition rate. Such a deposition may produce a depositionlayer having a thickness over the first surface that is less than 50% ofthe thickness over the second surface.

A variety of nucleation layer compositions are conceivable just as avariety of nucleation layer thicknesses and selectivities areconceivable. The second part of the nucleation layer on the secondsurface of the substrate may comprise a plurality of components alsocomprised by the first part. For example, the first and second parts ofthe nucleation layer may comprise silicon nitride. Further, the firstand second parts of the nucleation layer may even consist essentially ofthe same components in approximately same proportions. For example, thefirst and second parts of the nucleation layer may comprise anapproximately homogeneous composition. However, the composition of thefirst part of the nucleation layer may also differ from the compositionof the second part of the nucleation layer. In such a circumstance, thefirst and second parts of the nucleation layer may still both comprisesilicon nitride. In addition, the first part may further compriseoxygen, for example, as in silicon oxynitride.

The present aspect of the invention may further include forming amonolayer of a first chemisorbed specie on the first and second parts ofthe nucleation layer substantially non-selectively on the first part ofthe nucleation layer compared to the second part. Such non-selectiveformation of a monolayer of a first chemisorbed specie may occur eventhough the first surface of the substrate exhibits a property ofchemisorbing the first specie at a slower rate compared to the secondsurface. This circumstance indicates one advantage of the present aspectof the invention. Namely, the nucleation layer may operate to interfacebetween a deposition layer and a substrate to alter properties such thatdeposition occurs substantially non-selectively. The deposition methodmay further comprise forming a monolayer of a second chemisorbed speciedifferent from the first specie on the first specie layer. It may beadvantageous that the nucleation layer comprise a material alsocomprised by the first and second specie layers combined. For example,the first and second specie layers, in combination, may comprise siliconand nitrogen. The nucleation layer may similarly comprise silicon andnitrogen.

In another aspect of the invention, a deposition method includessimultaneously forming a first part of a nucleation layer on aninsulative oxide material and a second part of the nucleation layer on asemiconductive material. The nucleation layer may then be contacted withan initiation precursor. The method further includes forming aninitiation layer at least one monolayer thick on the first and secondparts of the nucleation layer substantially non-selectively on the firstpart of the nucleation layer compared to the second part. The methodfurther may comprise contacting the initiation layer with a depositionprecursor and forming a deposition layer at least one monolayer thick onthe initiation layer.

A variety of specific methods exist for forming the first part and thesecond part of the nucleation layer described in the various aspects ofthe invention above to achieve subsequent formation of a substantiallynon-selective monolayer or other deposition layer. The method selectedmay be in situ with regard to subsequent formation of the depositionlayer or it may be ex situ. ALD may itself comprise one example of an insitu method. For example, a substrate may be placed in a first chamberand the first and second parts of a nucleation layer formed thereon byALD. Without removing the substrate from the chamber, a monolayer of afirst chemisorbed precursor may then be formed on the nucleation layeralso by ALD.

Often, traditional ALD occurs within an often-used range of temperatureand pressure and according to established purging criteria to achievethe desired formation of an overall ALD layer one monolayer at a time.Even so, ALD conditions can vary greatly depending on the particularprecursors, layer composition, deposition equipment, and other factorsaccording to criteria known by those skilled in the art. Maintaining thetraditional conditions of temperature, pressure, and purging minimizesunwanted reactions that may impact monolayer formation and quality ofthe resulting overall ALD layer. Accordingly, operating outside thetraditional temperature and pressure ranges may risk formation ofdefective monolayers.

In accordance with the present aspect of the invention, observationsindicate that increasing temperature or pressure or both can produce theeffect of reducing the selectivity of an otherwise selective monolayerformation step. In the various aspects of the invention, temperature mayremain below about 550 Celsius (° C.) and pressure may remain belowabout 20 Torr. The increased temperature, pressure, or bothcorrespondingly increases the likelihood that a deposition specie willchemisorb substantially non-selectively on the first and second surfacesof the substrate as described above and shown in FIG. 3. Even thoughsuch a process regime risks defective monolayer formation, such processmay be used to form a nucleation layer by ALD. The deposition layer maybe formed in a traditional ALD process regime at lower temperature andpressure. For example, traditional ALD of silicon nitride may occur at atemperature of from about 400° C. to about 550° C. and a pressure ofless than about 100 milliTorr. Different ranges are also conceivable, asdeterminable by those skilled in the art, depending on depositionprecursors, nucleation layer composition, surface properties, and otherfactors. Depending on the desired properties of the deposition layer,such layer may also be formed by ALD outside the traditional ALD processregime.

Another example of an in situ method involves chemical vapor deposition(CVD). The general technology of CVD includes a variety of more specificprocesses, including, but not limited to, plasma enhanced CVD andothers. CVD is commonly used to form non-selectively a complete,deposited material on a substrate. One characteristic of CVD is thesimultaneous presence of multiple species in the deposition chamber thatreact to form the deposited material. Such condition is contrasted withthe purging criteria for traditional ALD wherein a substrate iscontacted with a single deposition specie and chemisorbs to a substrateor previously deposited specie. A nontraditional ALD process regime mayprovide simultaneously contacted species of a type or under conditionssuch that ALD chemisorption, rather than CVD reaction occurs.

As one example, U.S. patent application Ser. No. 09/619,449 filed Jul.19, 2000 by Garo J. Derderian and Gurtej S. Sandhu entitled “DepositionMethods” and assigned to Micron Technologies, Inc. discloses anontraditional ALD process and is herein incorporated by reference.Derderian et al. describe a deposition method including contacting asubstrate with a first initiation precursor and forming a first portionof an initiation layer on the substrate. At least a part of thesubstrate is contacted with a second initiation precursor different fromthe first initiation precursor and a second portion of the initiationlayer is formed on the substrate. The invention may includesimultaneously contacting a substrate with a plurality of initiationprecursors, forming on the substrate an initiation layer comprisingcomponents derived from each of the plurality of initiation precursors.However, the plurality of initiation precursors do not react together asin CVD. Rather, they chemisorb to the substrate, providing a surfaceonto which a deposition specie may next chemisorb to form a completelayer of desired material.

Under most CVD conditions, deposition of the material occurs largelyindependent of the composition or surface properties of an underlyingsubstrate. However, deposition rate can be a frequent issue inperforming CVD. High deposition rates are often desired to increaseproduction output as long as such rates do not significantly diminishthe quality of a deposited material. Accordingly, depending on theparticular type of CVD technique, a process regime is selected thatproduces as high a deposition rate as is possible without significantnegative impacts on material quality.

In the present aspect of the invention, deposition rate is a lesssignificant issue. Accordingly, observation indicates that lowerpressures, temperatures, plasma intensities, reactant concentrations,etc., than would otherwise be traditionally accepted may be used toproduce a nucleation layer. CVD of a nucleation layer may thus occur ata deposition rate that conventionally might not qualify for a suitableCVD process. For example, traditional CVD of silicon nitride may occurat a temperature between about 600° C. to about 800° C. and a pressurebetween about 100 milliTorr to about 2 Torr, depending on the selectedtemperature. If temperature is toward the low end of the range, thenpressure is generally toward the high end of the range to stay withinthe traditional process regime. Exemplary parameters for nontraditionalCVD of a nucleation layer may fall below one or both of such ranges orbe in the low end of both ranges. Different ranges are conceivable, asdeterminable by those skilled in the art, depending on depositionprecursors, substrate composition, surface properties, and otherfactors.

Since CVD is typically a non-selective form of deposition, thenon-traditional process regime can produce a suitable nucleation layerhaving a thickness of one atom or molecule or more. Specifically,formation of an approximately 4 to 6 Angstrom silicon nitride nucleationlayer from ammonia and dichlorosilane (DCS) has been achieved at apressure of less than approximately 1.5 Torr, a temperature ofapproximately 645° C., and a processing time of about 2 minutes.Depending on the CVD technique selected, the same reaction chamber ortool may be used. both for CVD of a nucleation layer and ALD of adeposition layer. Thus, the hybrid structure of the CVD nucleation layerand ALD deposition layer may be formed possessing the advantageousqualities of an ALD material and such formation may be accomplished insitu.

Further, forming a deposition layer may occur by unconventional CVD in aprocess regime so far outside conventional CVD that the deposition issubstantially selective. That is, multiple deposition species maycontact the substrate together in the deposition chamber. However,temperature and pressure are low enough that the thickness of thedeposition layer over a first part of a substrate is less than 50% of athickness of the deposition layer over a second part, as shown in FIG.2. Exemplary parameters include less than about 645° C. and less thanabout 500 milliTorr or perhaps different ranges, as determinable bythose skilled in the art, depending on above mentioned factors. In sucha process regime, pressure might bear a more significant effect onselectivity compared to temperature. The unconventional CVD processregime may be conducive to forming a deposition layer only about 1 to 5atoms or molecules thick. Accordingly, by using a nucleation layer inkeeping with the various aspects of the present invention,unconventional CVD may also be used to form a deposition layer.

As examples of ex situ processing, any of the above-described ALD or CVDtechniques may be used. A substrate may be placed in a first chamber andthe first and second parts of a nucleation layer formed on thesubstrate. The substrate may then be removed from the first chamber andplaced in a second chamber different from the first. Formation of an ALDprecursor monolayer or unconventional CVD layer may then occur in thesecond chamber. Accordingly, the first chamber may comprise any toolsuitable for accomplishing CVD or ALD.

The first chamber may further comprise any tool suitable foraccomplishing techniques such as rapid thermal nitridation (RTN), remoteplasma nitridation (RPN), techniques for accomplishing growth of amaterial (as opposed to deposition) on a substrate, and othertechniques. RTN, RPN, and other techniques can involve growth of anucleation layer non-selectively on first and second surfaces of asubstrate. RTN often occurs in an ammonia ambient at a temperature ofgreater than 700° C. Temperature may be limited to about 800° C. incircumstances where thermal budget limitations exist. RPN is performedsimilarly except that a plasma is used to provide reactive nitrogenradicals in a manner that provides reduction of process temperature.Accordingly, RPN may be preferred in a circumstance with a sensitivethermal budget.

Material growth techniques, for example RTN, RPN, and others, mayproduce a nucleation layer the composition and selectivity of which canbe influenced by the composition of the underlying substrate. Forexample, one potential substrate is one wherein first part 4 ofsubstrate 2 in FIG. 1 comprises BPSG and second part 6 comprisespolysilicon. BPSG comprises silicon, oxygen, boron, and phosphorous.Polysilicon comprises primarily silicon. Both materials comprisesilicon, accordingly, thermal growth techniques may produce asilicon-containing material grown on the substrate. Nitride growthtechniques may produce silicon nitride on both materials. However, thesilicon nitride material grown on BPSG may also include oxygen, forexample, the material may comprise silicon oxynitride. Usually, theboron and phosphorous dopants of BPSG will not be incorporated into thegrown material.

In some circumstances, one part of a substrate comprises silicon andanother part of the substrate does not comprise silicon. Whether anitride or other grown material will form on the substrate will dependon the susceptibility of the non-silicon-comprising material to suchgrowth technique. Accordingly, a grown nucleation layer may formsubstantially non-selectively on a substrate or it may form selectivelyon a substrate depending on the criteria discussed above. Nevertheless,it is conceivable within the various aspects of the invention that an exsitu processing method may form a first and a second part of anucleation layer simultaneously and substantially non-selectively on afirst and second surface of a substrate. Such may occur even though thefirst surface of the substrate exhibits a property of chemisorbing afirst precursor at a slower rate compared to the second surface.Deposition of a material may subsequently occur on the ex situ formednucleation layer also substantially non-selectively.

Another aspect of the invention holds specific application to formingcontainer capacitor structures. FIG. 5 shows a semiconductive waferconstruction 20 having partially formed dynamic random access memory(DRAM) cells formed thereon. Semiconductive wafer construction 20includes a semiconductive material 22, for example, a bulk siliconwafer, and a field oxide 23 formed on semiconductive material 22. Nodelocations 25, 27, and 29 are formed within semiconductive material 22.Word lines 24 are formed over field oxide 23 and word lines 26 areformed over semiconductive material 22. An oxide layer 32 formed overword lines 24 and 26 prevents diffusion of dopants within a BPSG layer34 into word lines 24 and 26. Capacitor openings 38 and 40 are formedthrough BPSG layer 34 to expose node locations 25 and 29, respectively.A storage node layer 36 is formed on BPSG layer 34 and in electricalconnection with node locations 25 and 29. Storage node layer 36 maycomprise polysilicon, or more preferably rugged polysilicon. Ruggedpolysilicon may include hemispherical grain polysilicon, spherical grainpolysilicon, etc.

Formation of silicon nitride as a capacitor dielectric on storage nodelayer 36 is desired. Formation of silicon nitride on BPSG layer 34 as adopant diffusion barrier is also desired. Formation of silicon nitrideas a capacitor dielectric by ALD offers the advantage of a thincapacitor layer that possesses low electrical tunneling probability andlow defect densities compared to traditional CVD silicon nitride.Simultaneous formation of silicon nitride over storage node layer 36 andBPSG layer 34 would also afford processing advantages. As describedabove, observation indicates that ALD of silicon nitride formspreferentially on polysilicon compared to BPSG. Accordingly, the variousaspects of the present invention allow formation of a nucleation layer(not shown due to its preferably small thickness) on storage node layer36 and BPSG layer 34 followed by formation of a deposition layer 42 asshown in FIG. 6 on the nucleation layer. The nucleation layer may beformed simultaneously and non-selectively on storage node layer 36 andBPSG layer 34. The nucleation layer may comprise silicon nitride, butmay instead comprise some other compound. Accordingly, the nucleationlayer may comprise a material that is not a suitable capacitordielectric and/or dopant diffusion barrier.

Examples of process conditions for forming nucleation layers depends onthe type of formation process and desired properties of the layer inkeeping with the aspect of the invention described above. A siliconnitride nucleation layer may be formed in situ in a low pressure CVD hotwall batch reactor at about 645° C. and about 1.5 Torr. Processing timemay be varied to form a layer of a thickness suitable for nucleation.Subsequently, a deposition layer may be formed on the nucleation layerwithin the low pressure CVD hot wall batch reactor. The deposition layermay be formed by ALD.

Alternatively, a silicon nitride nucleation layer may be formed ex situusing RTN at about 800° C. for about 60 seconds in an ammonia ambient.The substrate and nucleation layer may then be removed to a depositiondevice suitable for the deposition layer formation, such as by, ALD.

In compliance with the statute, the invention has been described inlanguage more or less specific as to structural and methodical features.It is to be understood, however, that the invention is not limited tothe specific features shown and described, since the means hereindisclosed comprise preferred forms of putting the invention into effect.The invention is, therefore, claimed in any of its forms ormodifications within the proper scope of the appended claimsappropriately interpreted in accordance with the doctrine ofequivalents.

1. A low selectivity deposition method comprising: forming a first partof a nucleation layer directly on a first surface of a substrate;forming a second part of a nucleation layer directly on a second surfaceof the substrate; and forming a deposition layer comprising achemisorbed first specie layer about one monolayer thick directly on thefirst and second parts of the nucleation layer substantiallynon-selectively on the first part of the nucleation layer compared tothe second part, even though the first and second surfaces of thesubstrate exhibit a property of the deposition layer forming lessreadily on the first surface compared to the second surface.
 2. Thedeposition method of claim 1 wherein the forming the first and thesecond part of the nucleation layer occurs by chemical vapor deposition.3. The deposition method of claim 2 wherein CVD of the nucleation layeroccurs non-selectively at a temperature no greater than about 645° C.and at a pressure of from about 500 milliTorr to about 1.5 Torr.
 4. Thedeposition method of claim 1 wherein the forming the first and thesecond part of the nucleation layer occurs by atomic layer deposition.5. The deposition method of claim 4 wherein the atomic layer depositioncomprises contacting the substrate with only one precursor specie at atime.
 6. The deposition method of claim 4 wherein ALD of the nucleationlayer occurs non-selectively at a temperature of from about 400 to about500° C. and at a pressure of from about 100 milliTorr to about 20 Torr.7. The deposition method of claim 1 wherein the forming the first andthe second part of the nucleation layer occurs simultaneously.
 8. Thedeposition method of claim 1 wherein the forming the first and thesecond part of the nucleation layer occurs simultaneously and thenucleation layer forms substantially non-selectively on the firstsurface of the substrate compared to the second surface.
 9. Thedeposition method of claim 1 wherein the forming the deposition layer isperformed in situ of the forming the first and the second part of thenucleation layer.
 10. The deposition method of claim 1 wherein thesecond part of the nucleation layer comprises a plurality of componentsalso comprised by the first part.
 11. The deposition method of claim 1wherein the first and the second parts of the nucleation layer comprisesilicon nitride, aluminum oxide, or tantalum oxide.
 12. The depositionmethod of claim 1 wherein the first and the second parts of thenucleation layer consist essentially of same components in approximatelysame proportions.
 13. The deposition method of claim 1 wherein acomposition of the first part of the nucleation layer differs from acomposition of the second part of the nucleation layer.
 14. Thedeposition method of claim 1 wherein the first and the second parts ofthe nucleation layer comprise silicon nitride and the first part furthercomprises oxygen.
 15. The deposition method of claim 1 wherein athickness of the nucleation layer comprises less than about 20Angstroms.
 16. The deposition method of claim 15 wherein the thicknesscomprises less than about 6 Angstroms.
 17. The deposition method ofclaim 1 wherein a thickness of the first part of the nucleation layer isgreater than 50% of a thickness of the second part.
 18. The depositionmethod of claim 17 wherein the thickness of the first part is greaterthan 80% of the thickness of the second part.
 19. The deposition methodof claim 1 wherein the chemisorbed first specie layer is one monolayerthick.
 20. The deposition method of claim 1 wherein the first surface ofthe substrate exhibits a property of chemisorbing the first specie at aslower rate compared to the second surface.
 21. The deposition method ofclaim 1 wherein the forming the deposition layer further comprisesforming a layer at least one monolayer thick of a chemisorbed secondspecie different from the first specie on the first specie layer. 22.The deposition method of claim 21 wherein the second layer consistsessentially of a monolayer.
 23. The deposition method of claim 21wherein the first and second specie layers, in combination, comprisesilicon and nitrogen.
 24. The deposition method of claim 21 wherein thenucleation layer comprises a material also comprised by the first andsecond specie layers combined.
 25. The deposition method of claim 21wherein forming the first and second parts of the nucleation layeroccurs simultaneously and comprises depositing a complete nucleationlayer in a single deposition, the complete nucleation layer and thecombined first and second specie layers consisting essentially of samecomponents in approximately same proportions.
 26. The deposition methodof claim 1 wherein the first and second parts of the nucleation layercomprise aluminum oxide.
 27. The deposition method of claim 1 whereinthe first and second parts of the nucleation layer comprise tantalumoxide.
 28. The deposition method of claim 1 wherein the forming thedeposition layer is performed ex situ of the forming the first and thesecond part of the nucleation layer.
 29. A low selectivity depositionmethod comprising: simultaneously forming a first part of a nucleationlayer on an insulative oxide material and a second part of thenucleation layer on a semiconductive material; and contacting thenucleation layer with an initiation precursor and forming an initiationlayer about one monolayer thick on the first and second parts of thenucleation layer substantially non-selectively on the first part of thenucleation layer compared to the second part.
 30. The deposition methodof claim 29 wherein the initiation layer is one monolayer thick.
 31. Thedeposition method of claim 29 wherein the first and the second parts ofthe nucleation layer consist essentially of same components inapproximately same proportions.
 32. The deposition method of claim 29wherein the first and the second parts of the nucleation layer comprisesilicon nitride and the first part further comprises oxygen.
 33. Thedeposition method of claim 29 wherein a thickness of the nucleationlayer comprises less than about 20 Angstroms.
 34. The deposition methodof claim 29 wherein a thickness of the first part of the nucleationlayer is greater than about 50% of a thickness of the second part. 35.The deposition method of claim 29 wherein the insulative oxide exhibitsa property of chemisorbing the initiation precursor at a slower ratecompared to the semiconductive material.
 36. The deposition method ofclaim 29 further comprising contacting the initiation layer with atleast one deposition precursor and forming a deposition layer at leastone monolayer thick on the initiation layer.
 37. The deposition methodof claim 36 wherein the deposition layer consists essentially of amonolayer.
 38. The deposition method of claim 36 wherein the depositionprecursor consists essentially of a single precursor specie.
 39. Thedeposition method of claim 36 wherein the initiation and depositionlayers, in combination, comprise silicon and nitrogen, or tantalum andoxygen, or aluminum and oxygen.
 40. The deposition method of claim 36wherein simultaneously forming the first and second parts of thenucleation layer comprises depositing a complete nucleation layer in asingle deposition, the complete nucleation layer and the combinedinitiation and deposition layers consisting essentially of samecomponents in approximately same proportions.
 41. The deposition methodof claim 29 wherein simultaneously forming the first and second parts ofthe nucleation layer comprises non-selective CVD at a temperature nogreater than about 645° C. and at a pressure of from about 500 milliTorrto about 1.5 Torr.
 42. The deposition method of claim 29 whereinsimultaneously forming the first and second parts of the nucleationlayer comprises non-selective ALD at a temperature of from about 400 toabout 500° C. and at a pressure of from about 100 milliTorr to about 20Torr.
 43. A low selectivity deposition method comprising: atomic layerdepositing a nucleation substance chemisorbed directly on a firstsurface and a second surface of a substrate substantiallynon-selectively, wherein the first surface exhibits a property ofchemisorbing an atomic layer deposition precursor at a slower ratecompared to the second surface and the nucleation substance exhibits aproperty of chemisorbing the precursor at an approximately equal rateover the first surface compared to over the second surface.
 44. Thedeposition method of claim 43 wherein the nucleation substance comprisesan approximately homogeneous composition over the first and the secondsurface.
 45. The deposition method of claim 43 wherein the nucleationlayer comprises silicon nitride and a nucleation layer part that is overthe first surface further comprises oxygen.
 46. The deposition method ofclaim 43 wherein a thickness of the nucleation layer comprises less thanabout 20 Angstroms.
 47. The deposition method of claim 43 wherein athickness of a nucleation layer part that is over the first surface isgreater than 50% of a thickness a nucleation layer part that is over thesecond surface.
 48. The deposition method of claim 43 wherein ALD of thenucleation substance occures at a temperature of from about 400 to 550°C. and at a pressure of from about 100 milliTorr to about 20 Torr.
 49. Alow selectivity deposition method comprising: placing a substrate in adeposition chamber; forming a first part of a nucleation layer directlyon a first surface of the substrate in the chamber; forming a secondpart of a nucleation layer directly on a second surface of the substratein the chamber; and without removing the substrate from the chamber,forming a layer about one monolayer thick of a first chemisorbedprecursor directly on the first and second parts of the nucleation layersubstantially non-selectively on the first part of the nucleation layercompared to the second part.
 50. The deposition method of claim 49wherein the forming the first and the second part of the nucleationlayer occurs simultaneously and the nucleation layer forms substantiallynon-selectively on the first surface of the substrate compared to thesecond surface.
 51. The deposition method of claim 49 wherein the firstsurface of the substrate exhibits a property of chemisorbing the firstprecursor at a slower rate compared to the second surface.
 52. Thedeposition method of claim 49 wherein the first surface comprisesborophosphosilicate glass and the second surface comprises polysilicon.53. A low selectivity deposition method comprising: placing a substratein a first chamber; forming a first part of a nucleation layer directlyon a first surface of the substrate in the first chamber; forming asecond part of a nucleation layer directly on a second surface of thesubstrate in the first chamber; removing the substrate from the firstchamber and placing it in a second chamber different from the first; andforming a layer of a first chemisorbed specie at least one monolayerthick directly on the first and second parts of the nucleation layer inthe second chamber substantially non-selectively on the first part ofthe nucleation layer compared to the second part.
 54. The depositionmethod of claim 53 wherein the forming the first and the second part ofthe nucleation layer occurs simultaneously and the nucleation layerforms substantially non-selectively on the first surface of thesubstrate compared to the second surface.
 55. The deposition method ofclaim 53 wherein the first surface of the substrate exhibits a propertyof chemisorbing the first specie at a slower rate compared to the secondsurface.
 56. The deposition method of claim 53 wherein the first surfacecomprises borophosphosilicate glass and the second surface comprisespolysilicon.